Differential feeding mechanism for sewing machines



June 2, 1936. A. B. CLAYTON DIFFERENTIAL FEEDING MECHANISM FOR SEWINGMACHINES Filed April 24} 1935 5 Sheets-Sheet 1 rewB. Clayion June 2,1936. A. B. CLAYTON 2,042,651

DIFFERENTIAL FEEDING MECHANISM FOR SEWING MACHINES Filed April 24, 19355 Sheets-Sheet 2 June 2, 1936. A. B. CLAYTON DIFFERENTIAL FEEDINGMECHANISM FOR SEWING MACHINES Filed April 24, 1955 5 Sheets-Sheet 3 WWWPatented June 2, 1936 UNITED STATES PATENT orF eE DIFFERENTIAL FEEDINGMECHANISM FOR SEWING MACHINES Application April 24, 1935, Serial No.17,955

10 Claims.

This invention relates to differential feeding mechanisms for sewingmachines and has for an object to provide a variable differentialfeeding mechanism of the treadle-controlled type which is of simplifiedand improved construction and which works smoothly and efficiently underhigh-speed operating conditions. A further object of the invention isthe provision of a treadlecontrolled auxiliary or differential feedingmechanism which may be applied to a conventional sewing machine having awell known form of main feeding mechanism, with a minimum of additionalparts and required alterations in the machine. The invention also aimsto improve and simplify the feeding mechanism disclosed in my priorUnited States Patent No. 1,602,427, of Oct. 12, 1926, and adapt it forcontrol by the operator without stopping the machine.

With the above and other objects in view, as will hereinafter appear,the invention comprises the devices, combinations, and arrangements ofparts hereinafter set forth and illustrated in the accompanying drawingsof a preferred embodiment of the invention, from which the severalfeatures of the invention and the advantages attained thereby will bereadily understood by those skilled in the art.

In the accompanying drawings, Fig. 1 is a top plan view of the bed of a,sewing machine embodying the invention. Fig. 2 is a left end elevationof the machine bed with certain parts of the differential feedcontrolling mechanism removed. Fig. 3 is a similar view with the removedparts added. Fig. 4 is a rear side elevation of the feeding mechanism.Fig. 5 is a disassembled perspective view of the treadle controlledauxiliary-feed-adjusting lever and its supporting parts. Fig. 6 is adisassembled perspective view showing the reverse sides of thesupporting parts shown in Fig. 5. Fig. 7 is a. section on the line l"l,Fig. 1, and Fig. 8 is a section on the line 8-8, Fig. 3.

l represents the bed of a sewing machine from which rises the lugs 2 and3 fitted with bearing bushings 4 and 5 for the main shaft 6 whichextends lengthwise of the bed i and includes the usual inclinedactuating crank 1 for the conventional loopers B. The bed i carries atone end the usual bracket-arm standard I shown in section in Fig. l.Rising from the other end of the bed I are the supporting means or postsU, I for the usual throat-plate I having the feed-dog slots l Theend-portion 6 of the main shaft 6 is journaled in the bearing bracket 9which is detachably secured to the grooved seat I!) in the post I bymeans of a screw l2.

The main feeding mechanism is of usual construction and comprises themain feed-dog I3 carried by the main feed-bar l4 fulcrumed on the pin 15carried by the feed-rocker it which, in turn, is carried by the fulcrumpin ll journaled in the base lugs E8. The main feed-bar M is disposed asusual at the inner side of the throatplate supporting posts l I, i. e.,at the side of such posts nearer the frame-standard W. The feed-rockerI6 is connected by the pin I9 to one end of the pitman 2B which at itsother end embraces the usual adjustable feed-advance eccentric 2| on themain shaft 6. Rising and falling movements are imparted to the mainfeedbar H! by means of the feed-lift eccentric 22 on the main shaft 6;the eccentric 22 being embraced by one strapped end of a pin 23 which isslidably received inthe apertured arm 2d of the feed-bar, The parts sofar described are conventional and well known.

The auxiliary or differential feed mechanism comprises the auxiliaryfeed-dog 25 carried by ,the upstanding auxiliary feed-bar 26 which isfulcrumed at 21, substantially vertically below the auxiliary feed-dog25, on the crank-arm 2i fixed to one end of the rock-shaft 29 journaledin the post 1 and the bearing lug 3!! on the bed I. The auxiliaryfeed-bar 26 is disposed at the outer side of the throat-plate supportingposts l t i. e., at the side of such posts more remote from the framestandard E The rock-shaft 29 has fixed .to its other end an arm 3! whichis forked to embrace the slide-blocks 32 bearing upon the auxiliaryfeed-lift eccentric 33 on the main shaft 6. The feed-lift eccentrics 22and 33 are timed to lift their respective feed-dogs l3 and 25simultaneously.

Theupstanding auxiliary feed-bar 25 is formed with an arcuate slot 34which is freely entered by a stud-pin 35 on the forward end of the link36, Fig. 2, which is disposed at the outer side of the posts P, I", andat its rearward end is connected to the fulcrum-pin A5 for the mainfeed-bar M. The arcuate slot 3 is concentric with the pin l5 at thebeginning of the feed-stroke of the parts. The link 3.6 is disposed atthe end of the sewing machine bed I and is in position for ready appli--cation to and manipulation by the treadle-controlled mechanism to bedescribed.

Secured to the bearing bracket 9 by means of the screw 12 and akey-piece 38 is the bracket 39 to which is fulcrumed at the point 48adjacent the auxiliary feed-bar 26, the treadle-controlled lever 4|disposed substantially, horizontally at the outer side of the link 36and having fixed to the inside face thereof the horizontally slottedblock 42 embracing the roller-stud 31 on the outer side of the link 36.A down-pull on the treadlechain 43 connected to the rear end of thelever 4| adjacent the feed-rocker l6 lowers the front end of the link 36in the arcuate slot 34 of the auxiliary feed-bar and increases thestroke of the auxiliary feed-dog 25 to effect a fulling in of i thework.

The lever 4| has a downwardly extending arm 44 adjacent its fulcrum 40and this arm carries an adjustable stop screw 45 arranged to engage thebearing bracket 9, Fig. 3, and limit the recovery motion of the lever 4|under the influence of the recovery spring 46, when the pull on thetreadle-chain is relieved; the spring 46 being connected at one end tothe arm 44 and at its other end to a pin 41 on the bracket 39.

To hold the lever 4| closely alongside the bracket 39, the latter isformed with an arcuate slot 48 through which freely passes the screw 49tight in the lever 4|.

The down-motion of the lever 4| may be arrested at any desiredpredetermined point by means of a stop-plate 50 ,held in any desiredposition of vertical adjustment by means of screws 5| passing throughthe vertical slot, 52 in the stop-plate 50.

From-the foregoing it will be seen that the auxiliary feeding mechanismcomprises a simple addition to the conventional main feeding mechanismof the machine and that it is instantly responsive to the will of theoperator to either full in the work or feed it to the same extent as themain feed mechanism. Due to the exposed position of thetreadle-controlled lever 4| and its supporting bracket 39, these partsare readily applied to or removed from the machine, without disturbanceof the feeding mechanism proper.

In the operation of the mechanism, the endwise movable link 36, whichconnects the main feed-bar l4 and feed-rocker Hi to the slottedauxiliary feed-bar 26, is guided in its movements by the slottedguide-block 42 on the treadle-controlled lever 4|. The slotted auxiliaryfeed-bar rises and falls relatively to the stud-screw 35 at the forwardend of the link 36 which transmits the rocking feed-and-return movementsof the feed-rocker Hi to the auxiliary feed-bar 26.

Having thus set forth the nature of the invention, what I claim hereinis:

1. In a sewing machine, a main shaft, main and auxiliary feedingmechanisms including main and auxiliary feed-bars with separate. andindependent supporting means therefor at opposite sides of said mainshaft, one of said feed-bars having an arcuate slot, a link connectionbetween said feed-bars, means at one end of said link freely received insaid arcuate slot, and means for guiding said link. r

2. In a sewing machine, a main shaft, main and auxiliary feedingmechanisms including main and auxiliary feed-bars with separate andindependent supporting means therefor at opposite sides of said mainshaft, one of said feed-bars having an arcuate slot, a link connectionbetween said feed-bars, means at one end of said link freely received insaid arcuate slot, and manually controlled means for positioning andguiding said link.

3. In a sewing machine, a main shaft, main and auxiliary feedingmechanisms including main and auxiliary feed-bars with separate andindependent supporting means therefor at opposite sides of said mainshaft, one of said feed-bars having an arcuate slot, a link connectionbetween said feed-bars, means at one end of said link freely received insaid arcuate slot, and a manually controlled lever connected to saidlink intermediate the ends of the latter for operatively supporting andguiding the same.

4. A sewing machine having a standard, a bed, and a main shaft extendinglengthwise of and journaled on said bed, throat-plate supporting meansrising from said bed, a throat-plate mounted on said supporting meansand formed with feed-dog slots, a main feed-bar at the inner side ofsaid throat-plate supporting means nearer the sewing machine framestandard, a main feeddog carried by said main feed-bar, a feed-rocker towhich said main feed-bar is pivotally connected, a feed-advanceeccentric on the main shaft connected to actuate said feed-rocker, amain feed-lift eccentric on the main shaft connected to said mainfeed-bar, an upstanding slotted auxiliary feed-bar at the outer side ofsaid supporting means more remote from the frame-standard, an auxiliaryfeed-lift eccentric on the main shaft and mechanism for imparting risingand falling movements to said auxiliary feed-bar, a link connection atthe outer side of said supporting means between the slotted portion'ofsaid auxiliary feed-bar and said main feed-rocker, and treadlecontrolledmechanism at the outer side of said link for shifting the latterrelative to said auxiliary feed-bar.

5. A sewing machine having a standard, a bed, and a main shaft extendinglengthwise of and journaled on said bed, throat-plate supporting meansrising from said bed, a throat-plate mounted on said supporting meansand formed with feed-dog slots, a main feed-bar at the inner side ofsaid throat-plate supporting means nearer the sewing machine framestandard, a main feeddog carried by said main feed-bar, a feed-rocker towhich said main feed-bar is pivotally connected, a feed-advanceeccentric on the main shaft connected to actuate said feed-rocker, amain feed-lift eccentric on the main shaft connected to said mainfeed-bar, an upstanding slotted auxiliary feed-bar at the outer side ofsaid supporting means more remote from the frame-standard, anauxiliary-feed-lift eccentric on the main shaft and mechanism forimparting rising and falling movements to said auxiliary feed-bar, alink connection at the outer side of said supportingmeans between theslotted portion of said auxiliary feed-bar and said main feed-rocker,treadle-controlled mechanism at the outer side of said link for shiftingthe latter relative to said auxiliary feed-bar, said mechanismcomprising aspring-biased lever disposed substantially horizontallyalongside said link and connected to the latter, said lever having 'afixed fulcrum adjacent said auxiliary feed-bar and a free end disposedrearwardly of said fixed fulcrum and adjacent said feed-rocker.

6. In a sewing machine, a main shaft, a main feed-rocker in rear of saidmain shaft, a main feed-bar connected to said feed-rocker, a mainfeed-eccentric on said main-shaft and connections for operating saidmain feed-rocker, a main feed-lift eccentric on said main shaft forimparting rising and falling movements to said main feed-bar, anauxiliary feed-lift rock-shaft disposed in front of said main shaft, anauxiliary feed-lift eccentric on said main shaft connected to actuatesaid rock-shaft, a crank-arm on said rock-shaft, an upstanding auxiliaryfeed-bar carried at its lower end by said crank-arm and formed with aslot, a direct link connection between the slotted portion of saidauxiliary feedbar and said main feed-rocker, and manually controlledmeans for shifting one end of said link along said slot to vary theamplitude of motion imparted to the auxiliary feed-bar by saidfeedrocker, without stopping the machine.

7. The combination with a sewing machine bed and main feeding mechanismcarried thereby and including a main feed-rocker, of auxiliary feedingmechanism including an auxiliary feeddog, a slotted auxiliary feed-bar,a direct linkconnection between the main feed-rocker and slottedauxiliary feed-bar, and means for shifting said link relative to saidslotted auxiliary feed-bar comprising a treadle-controlled leverdisposed alongside said link, a bracket on which said lever is fulcrumedat a point remote from said feed-rocker, and a connection between saidlink and treadle-controlled lever.

8. In a sewing machine, a bed casting a main shaft journaled in said bedcasting, a bearing" block for one extreme end of the main shaftdetachably mounted on said bed-casting, main and auxiliary feedingmechanisms driven by said main shaft, and treadle-controlled means forvarying the feeding action of said auxiliary feeding mechanismcomprising, a supporting bracket fixedly mounted on said detachablebearing block, and a treadle-controlled spring-biased lever fulcrumed onsaid bracket and connected to said auxiliary feeding mechanism.

9. In a sewing machine, a rectangular bed, a main shaft journaledlengthwise of said bed, main feeding mechanism including a mainfeedrocker fulcrumed on said bed in rear of the main shaft, a mainfeed-bar fulcrumed at its rear end on said feed-rocker, a main feed-dogmounted at the forward end of said main feed-bar, a slotted auxiliaryfeed-bar disposed in front of said main shaft, means for raising andlowering said auxiliary feed-bar, a link connected at its rear end tosaid main feed-rocker and shiftably connected at its front end to saidslotted auxiliary feed-bar, a treadle-controlled lever disposedalongside said link and fulcrumed at its front end at a fixed point infront of the main shaft and interconnecting means between the ends ofsaid lever and link.

10. In a. sewing machine, a main shaft, a main four-motion feedingmechanism, an auxiliary four-motion feeding mechanism, said mechanismsincluding substantially horizontal main and upstanding auxiliaryfeed-bars respectively supported independently of one another in rearand in front of said main shaft, a link pivotally connected at its rearend to said main feeding mechanism and at its front end freely connectedto said auxiliary feed-bar to transmit feed-andreturn movements to thelatter, a treadle-controlled lever having a fixed fulcrum, and aconnection between said treadle-controlled lever and said link forsupporting and guiding the latter in its endwise movements.

ANDREW B. CLAYTON.

